The present invention relates to a computercontrolled password lock, and more particularly to a computer-controlled password lock with its password varying with time.
There are a variety of computer-controller password locks commercially available on the market. --For example, such a computer-controlled lock system is disclosed in U.S. Pat. No. 3,953,769 to Sopko, wherein a keyboard is mounted on the outside of a door and is connected to computer-controlled circuitry enclosed in a housing mounted on the inside of the door to control energization of a deadbolt solenoid. Such a lock system permits a user to open the lock by keying in a correct numeral password from its keyboard, thereby preventing it from being opened with a master key by a thief. With such a computer-controlled lock, the user need not bring a key with him, so that it is not only convenient, but also able to eliminate the possibility of losing the key. In addition, the user can reset the password of the lock as desired, and thus need not worry about anybody, including the one who sells the lock, being aware of the password. Although conventional computer-controlled password locks have the above advantages, they still have several drawbacks, such as the user must memorize a password of four or more figures, and that the length of the password cannot be adjusted. In addition, since the user frequently selects his birthday, part of his telephone number of identification card number, or the like as the password to facilitate memorization, somebody who familiarizes himself with the user may guess at the password.